Problem: On the way to school, Karen became fixated on the puzzle game on her phone!

<image>

The game is played as follows. In each level, you have a grid with n rows and m columns. Each cell originally contains the number 0.

One move consists of choosing one row or column, and adding 1 to all of the cells in that row or column.

To win the level, after all the moves, the number in the cell at the i-th row and j-th column should be equal to gi, j.

Karen is stuck on one level, and wants to know a way to beat this level using the minimum number of moves. Please, help her with this task!

Input

The first line of input contains two integers, n and m (1 ≤ n, m ≤ 100), the number of rows and the number of columns in the grid, respectively.

The next n lines each contain m integers. In particular, the j-th integer in the i-th of these rows contains gi, j (0 ≤ gi, j ≤ 500).

Output

If there is an error and it is actually not possible to beat the level, output a single integer -1.

Otherwise, on the first line, output a single integer k, the minimum number of moves necessary to beat the level.

The next k lines should each contain one of the following, describing the moves in the order they must be done:

  * row x, (1 ≤ x ≤ n) describing a move of the form "choose the x-th row". 
  * col x, (1 ≤ x ≤ m) describing a move of the form "choose the x-th column". 



If there are multiple optimal solutions, output any one of them.

Examples

Input

3 5
2 2 2 3 2
0 0 0 1 0
1 1 1 2 1


Output

4
row 1
row 1
col 4
row 3


Input

3 3
0 0 0
0 1 0
0 0 0


Output

-1


Input

3 3
1 1 1
1 1 1
1 1 1


Output

3
row 1
row 2
row 3

Note

In the first test case, Karen has a grid with 3 rows and 5 columns. She can perform the following 4 moves to beat the level:

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In the second test case, Karen has a grid with 3 rows and 3 columns. It is clear that it is impossible to beat the level; performing any move will create three 1s on the grid, but it is required to only have one 1 in the center.

In the third test case, Karen has a grid with 3 rows and 3 columns. She can perform the following 3 moves to beat the level:

<image>

Note that this is not the only solution; another solution, among others, is col 1, col 2, col 3.

Solution (in JAVA):

Solution:
import java.io.*;
import java.util.*;

public class A {

    static BufferedReader in;
    static PrintWriter out;
    static StringTokenizer tok;

    public static void main(String[] args) throws IOException {
        try {
            in = new BufferedReader(new FileReader("input.txt"));
            out = new PrintWriter(new File("output.txt"));
        } catch (Exception e) {
            in = new BufferedReader(new InputStreamReader(System.in));
            out = new PrintWriter(new OutputStreamWriter(System.out));
        }
        tok = new StringTokenizer("");
        new A().solve();
        out.flush();
        out.close();
    }

    String nextTok() throws IOException {
        while (!tok.hasMoreTokens()) {
            tok = new StringTokenizer(in.readLine());
        }
        return tok.nextToken();
    }

    String nextLine() throws IOException {
        return in.readLine();
    }

    int nextInt() throws IOException {
        return Integer.parseInt(nextTok());
    }

    long nextLong() throws IOException {
        return Long.parseLong(nextTok());
    }

    double nextDouble() throws IOException {
        return Double.parseDouble(nextTok());
    }

    class Pair {
        int x;
        int y;
        Pair(int x, int y) {
            this.x = x;
            this.y = y;
        }
    }
    
    class Tri {
        int x;
        int y;
        int g;
        Tri(int x, int y, int g) {
            this.x = x;
            this.y = y;
            this.g = g;
        }
    }
    
    int arr[][];
    StringBuilder sb = new StringBuilder();
    
    int calcRow() {
        int cnt = 0;
        for (int i = 0; i < arr.length; i++) {
            int min = Integer.MAX_VALUE;
            for (int j = 0; j < arr[i].length; j++) {
                min = Math.min(min, arr[i][j]);
            }
            cnt += min;
            for (int j = 0; j < arr[i].length; j++) {
                arr[i][j] -= min;
            }
            for (int j = 0; j < min; j++) {
                sb.append("row "+(i+1)+"\n");
            }
        }
        return cnt;
    }
    
    int calcCol() {
        int cnt = 0;
        for (int j = 0; j < arr[0].length; j++) {
            int min = Integer.MAX_VALUE;
            for (int i = 0; i < arr.length; i++) {
                min = Math.min(min, arr[i][j]);
            }
            cnt += min;
            for (int i = 0; i < arr.length; i++) {
                arr[i][j] -= min;
            }
            for (int i = 0; i < min; i++) {
                sb.append("col "+(j+1)+"\n");
            }
        }
        return cnt;
    }
    
    void solve() throws IOException {
        int n = nextInt();
        int m = nextInt();
        arr = new int[n][m];
        for (int i = 0; i < n; i++) {
            for (int j = 0; j < m; j++) {
                arr[i][j] = nextInt();
            }
        }
        int all = n < m ? calcRow()+calcCol() : calcCol()+calcRow();
        for (int i = 0; i < n; i++) {
            for (int j = 0; j < m; j++) {
                if (arr[i][j] != 0) {
                    out.println(-1);
                    return;
                }
            }
        }
        out.println(all);
        out.println(sb.toString().trim());
    }

}